[Advances in diagnostic procedures for detection of pheochromocytoma]

Pheochromocytoma arises from chromaffin tissue, usually in the adrenal medulla, and is a cause of curable hypertension. In most cases, clinical acumen alone is not sufficient to diagnose pheochromocytoma. Therefore, the diagnosis of this disorder has become almost totally dependent on laboratory test results. The most widely used biochemical procedures for detection of pheochromocytoma are measurements of urinary catecholamines or their metabolites, such as vanillylmandelic acid (VMA) or total metanephrine (MN). Traditional spectrophotometric and fluorometric methods for urinary catecholamines and their metabolites are being replaced by highly sensitive and selective chromatographic methods. Plasma noradrenaline and adrenaline measurements are of additional diagnostic value in determining recent catecholamine release and response to clonidine suppression. For either urine or plasma measurements, appropriate patient preparation, sample collection and method validation along with an understanding of the variable pattern of catecholamine secretion and metabolism in pheochromocytoma are essential. Localization of tumors is important for the surgeon and is accomplished by CT scan, 131I-metaiodobenzylguanidine scintiscans or abdominal aortography.